Why do scabs form?

As soon as you scrape or break the skin anywhere on your body, special blood cells called platelets get to work. Platelets stick together like glue at the cut site, forming a clot. This clot is like a protective bandage over your cut that keeps more blood and other fluids from flowing out. The clot is also full of other blood cells and thread-like matter called fibrin that help hold the clot together. As the clot starts to get hard and dries out, a scab forms. Crusty and dark red or brown, the scab protects the cut by keeping germs out and giving the skin cells underneath a chance to heal. All by itself, usually after a week or two, a scab falls off, revealing pinkish, new skin underneath.